What are the best games for my Android phone?

hi i have a Samsung Galaxy S (i9000) smartphone and i'm looking for the best games for my Android phone.

can be either free or paid but i'm looking for something that is quite similar or in the style of games such as Sonic the hedghog, Metal Slug, Super Mario Bros. or a space shooter or a medieval game. one that i can play on a long haul flight or a long train ride.

any sugestions please?

thanks.